Though current conventional bicycles are intended to travel quickly, they are not able to achieve the speeds of bicycles equipped with the present invention. To achieve higher rates of speed than are currently obtainable by current conventional bicycles, the gear ratio between the crank sprocket and the gears on the rear wheel free wheel mechanism must be increased. One way to achieve this goal is to drastically increase the diameter of the crank sprocket.
Enlarged diameter crank sprockets have been used on multi-wheeled cycles, such as tricycles and polycycles. For example, U.S. Pat. Nos. 1,093,729 and 363,189 describe enlarged diameter crank sprockets. These prior art sprockets appear to be located in the middle of the pedal crank shafts. These multi-wheeled cycle crank sprockets can be larger than conventional bicycle sprockets as the sprockets are free from a bicycle's structural constraints and are subject to different forces. In addition, the multi-wheeled cycles containing the enlarged crank-sprockets are not used to obtain the high speeds possible with the present invention.
Bicycles with drastically enlarged crank sprockets are not known to exist on conventional bicycles. This is apparently due to several reasons. Conventional bicycle frames cannot accommodate enlarged diameter crank sprockets. An enlarged bicycle crank sprocket if placed on the hub in the original position of a conventional crank sprocket could not rotate in a plane parallel to the bicycle frame without coming in contact with a chain stay rail of the frame.
In addition, if the enlarged crank sprocket is extended away from the hub to clear this chain stay rail and is constructed similarly to a conventional crank sprocket, the enlarged crank sprocket would be unstable and would wobble and not rotate in a plane parallel to the frame. This wobbling would reduce a peddler's ability to produce torque (and, therefore, speed) and ultimately may cause the chain to derail. In addition, an extended enlarged crank sprocket would eventually warp or buckle. These problems are compounded in the case of multi-speed bicycles.
Accordingly, it is desired to provide a multi-speed bicycle capable of achieving high speed utilizing an enlarged crank sprocket.